Traffic lights are typically automatically controlled under repeating timing cycles for each light. Municipal authorities usually determine ordinary, predictable traffic volume, and adjust light length cycles accordingly. It is occasionally necessary for police officers and other municipal authorities to override and modify automated traffic light control sequences. A temporary activity which changes the usual traffic patterns is typically a cause for such necessity. A sports or theatrical event at a church or school, a collision between two vehicles, and displacement of traffic from other roads are some examples of temporary activities which could cause delays and backups at a particular intersection which is controlled by a traffic light which is under automatic control.
If an automated traffic light controller is to be modified, this ordinarily becomes a two-person operation. One of the two must be located proximate the traffic light controller or control box, which is typically located proximate the roadway or intersection being controlled. Manufacturers of traffic lights and their controllers have anticipated this need, and have provided a plug-in connection in the control box for entering commands which override the automated sequences. Commands may be entered by a hand held controller which may be a pushbutton controller or other manually operated device. The hand held controller has a cord and terminal which provides a hard wired or continuous mechanical and electrical communications line to the control box. The manually entered commands cause the controller to implement the next phase of the pre-established automated sequence. However, such commands are not remembered, so that the person entering these commands must remain with the controller and continue to enter commands as long as he or she wishes to override the automated sequences.
While this enables manual overriding control of the traffic light, it nonetheless has adverse consequences. One is that the police officer or other personnel controlling the traffic light is located at a vantage point which is usually far from optimal in observing traffic conditions. The second person is usually required to be located at a favorable vantage point for observing traffic, so as to determine when to change the traffic light control sequence. A second adverse consequence is that these two must communicate with one another to assure efficient and appropriate management of the traffic light. This communication can be cumbersome and subject to misunderstandings, and still does not address the problem of tying up two people to manage a traffic light.
Remote traffic controllers which enable one person to manage a traffic light from a location remote from the control box are known. However, traffic light boxes, as ordinarily supplied and installed, do not have means for communicating remotely. Rather, each has a plug-in terminal for receiving the known prior art hand held controller. Apparatus enabling remote communication could be provided at existing traffic light controllers, but this entails great additional expense in that every traffic light controller must then be furnished with a suitable interface device. This solution, while technically feasible, would impose significant and objectionable costs to the municipality operating those traffic lights.
There remains a need for a traffic light controller which reduces the demand for personnel in temporarily overriding automated traffic light control, and which does not impose undue costs of modification to existing traffic light controllers.